1. Field
Apparatuses and methods consistent with the exemplary embodiments generally relate to encoding and decoding an image, and more particularly, to a method and apparatus for encoding an image using an orthogonal transform.
2. Description of the Related Art
A codec such as Moving Pictures Experts Group (MPEG)-4 H.264/MPEG-4 Advanced Video Coding (AVC) performs prediction encoding of an image using intra or inter prediction. For the inter prediction, an image encoding apparatus generates a prediction block by searching a reference picture for a block identical or similar to a current block and performing motion compensation of the current block based on the searching result. For the intra prediction, an image encoding apparatus generates a prediction block by using a value of pixels included in a previously encoded area adjacent to a current block.
Once the prediction block is generated, a residual block is generated by subtracting the prediction block from the current block, and an orthogonal transform is performed on the generated residual block. The orthogonal transform may include a Discrete Cosine Transform (DCT).